1. Field of the Invention
The present invention relates to improvement of an information recording apparatus and method for recording information on a recording medium such as an optical disc or the like on/from which information can be written/read out. The present invention also relates to an information reproduction apparatus and method for reproducing information recorded on the recording medium.
2. Description of the Related Art
As is well known, recently, data rewritable optical discs have been developed and put into practical use. As data rewritable optical discs, for example, DVD (Digital Versatile Disc)-RAM (Random Access Memory), DVD-RW (Rewritable), and the like have prevailed.
In a data rewritable optical disc, when the user records, as digital data to be recorded, data as a long run of only one of two values, symmetry of RF (Radio Frequency) signals read upon reproduction is lost, thus adversely influencing various servo systems.
For this reason, digital data to be recorded undergoes a scramble process based on a scramble pattern generated by a pseudo random number generator or the like, so as to control one and the other values of data to have nearly equal frequencies of generation upon recording.
On the other hand, in the DVD format, digital data to be recorded is segmented into predetermined reference units called sectors, and is recorded on an optical disc while assigning addresses for respective sectors. In this case, the scramble process for digital data to be recorded is done for each sector, and scramble patterns to be used are permanently determined for respective addresses.
For this reason, in case of data such as management data, which is recorded at a predetermined location on an optical disc, is often changed only partially, and is rewritten entirely in a rewrite process, identical data undergoes a scramble process using an identical scramble pattern, and is repetitively recorded at an identical position on the optical disc.
In this case, since the scramble process of identical data using an identical scramble pattern always has an identical result, repetitively writing the scrambled data at an identical position on the optical disc consequently means to repetitively write identical data at an identical position on the optical disc.
However, when identical digital data is repetitively written at an identical position in response to every rewrite request like the management data, the rewrite life of the optical disc on which data is recorded using phase change marks may be impaired.